The three different approaches to measuring the GDP are the expenditure approach, the blank approach, the blank approach and blank . The expenditure approach aggregates the spending by the four sectors of the economy: (a) the household sector, (b) the blank sector, (c) the blank sector, and (d) the foreign sector, to yield the total GDP. The largest spending in Canada's aggregate GDP comes from the blank sector. When using the income approach, the first step is to calculate the total national income by adding employee compensation, proprietor's income, blank , net interest, and rental income